At present, with the improvement of prenatal diagnosis techniques, surgical techniques, use of chemotherapeutic drugs, and standardized treatment, the cure and survival rates of sacrococcygeal teratoma have been significantly improved, and thus the occurrence of tumor recurrence or even malignancy after surgery has become a prominent problem in the treatment of sacrococcygeal teratoma and has affected the prognosis of this group of children. According to the literature, the overall recurrence rate of sacrococcygeal teratoma ranges from 2% to 35% (average 12.5%), and there are significant differences in recurrence in different pathological tissues, with the recurrence rates of mature, immature, and malignant teratomas being 0%-26% (average 10%), 12%-55% (average 33%), and 0%-36% (average 18%), respectively. By analyzing the recurrence cases of sacrococcygeal teratoma in our hospital, it was found that the recurrence in our hospital was similar to that reported in the literature (total recurrence rate 16.4%), and that immature teratoma (33.3%) was also the pathological type with the highest recurrence rate, considering that it may be because the recurrence rate was reduced by chemotherapy with sensitive drugs such as platinum for malignant tumors, while surgical treatment only for grade I-II immature teratoma was the possible The reason for this phenomenon is surgery only. In our data, there were 16 cases of recurrence, except for one case in which tumor recurrence was delayed until 59 months because of sacrococcygeal pain, all the children showed symptoms of tumor recurrence within 3 years after stage I surgery, in which the average time of recurrence of benign teratoma lagged significantly behind the other two pathological types, and there were even reports of recurrence of benign teratoma 20 years after surgery in the literature. We also observed that all children with recurrence of malignant teratoma were found on routine postoperative examination, while only two cases of benign lesions were found on routine review. Therefore, we believe that regular postoperative follow-up is crucial regardless of the pathological nature of sacrococcygeal teratoma, especially for benign teratoma, which does not easily attract the attention of families and physicians, and therefore regular and regular follow-up for at least 3 years is needed so that tumor recurrence can be detected as early as possible, rather than waiting until clinical symptoms appear before consultation. The rate of malignancy of sacrococcygeal teratoma not only increases gradually with age, but also is prone to malignancy after recurrence of benign teratoma. More than half (5/9) of the children in our group had a change in pathological nature, i.e., from mature teratoma to immature or malignant teratoma. It has been suggested that this shift in pathological type may be related to the undetected malignant component of the tumor specimens removed in the first stage surgery on the one hand, and to the intraoperative tumor remnants and the shift in the biological characteristics of the residual tumor on the other hand. In our data, among the 5 children with pathological nature transformation after recurrence, 3 cases had intraoperative ulceration of parenchymal tumor components and 2 cases had intraoperative residual tumor, thus we speculate that intraoperative ulceration of parenchymal tumor components and residual tumor may also be one of the causes of malignant transformation after recurrence of tumor. It is generally believed that the pathological nature of malignancy, incomplete resection of the tumor, ulceration of the tumor, and unresected caudal bone are the high-risk factors for the recurrence of sacrococcygeal teratoma after surgery. Our data found that malignant teratoma, incomplete resection of the tumor, and ulceration of the parenchymal component of the tumor were risk factors for recurrence of sacrococcygeal teratoma. Although the tumor recurrence rate gradually increased with age and tumor volume, the results of univariate regression analysis showed that they were not risk factors for tumor recurrence. The results also showed that the recurrence rate of Altman class IV was significantly higher than the other three classes, which was related to the higher proportion of malignant tumor cases in type IV, but the Altman classification was also not a risk factor for tumor recurrence. Our data also showed that the intraoperative recurrence rate of pure cystic fluid ulceration (18.2%) was similar to that of tumor without ulceration (15.4%), thus suggesting that we should not ignore the ulceration of parenchymal component when dealing with huge tumors with predominantly cystic component intraoperatively, and also ensure complete resection of tumor as much as possible through proper drainage of cystic fluid to reduce tumor recurrence. The recurrence of sacrococcygeal teratoma has a negative impact on the prognosis, therefore, only by paying sufficient attention to the risk factors causing tumor recurrence and reducing tumor recurrence can we further improve the survival rate and treatment outcome of sacrococcygeal teratoma.